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Horsetan

SSM GNR(I) "S"-class 4-4-0

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The next bit is the smokebox wrapper. In the pre-"Weshty" days, and certainly in my sample, the wrapper was supplied partly-rolled - or rather, it was curved into a wide arc, and that's yer lot. The rest was up to the builder. To roll it even further to match the curvature of the smokebox shell is not easy, but you can use either one of two methods:

 

1. Get a 1/2 inch brass or steel bar / tube, put the wrapper strip under it, and roll it like a rolling pin on your thigh, or possibly even the carpet; or

 

2. If you have a proper rolling mill, you can form the right curves very quickly. Rolling mills, though expensive to buy, mean you can roll all sorts of smokeboxes and boilers (parallel or tapered). I bought mine years ago from GW Models, and it has been incredibly convenient. That said, the "S" smokebox wrapper was first rolled from a bare arc to a tight cylinder, matching the radius of the smokebox shell front and rear.

 

You then have to mark out points at which the smokebox wrapper has to be reverse-rolled to represent the vertical sides. The fixed point is at the top dead centre, where the lamp bracket has a half-etched mark on both the smokebox shell front overlay, and the wrapper itself. Using a scriber point, I more-or-less worked out that the reverse curve would have to be around the fourth or fifth rivet position from the base.

 

This photo shows the scriber pointing to the relevant (front) line of rivets, and you should be able to see a mark I made about four rivets above that - that's where the reverse curve will be:

 

attachment.php?attachmentid=10954&d=1387806864

 

I also scribed a straight line at this point from the rear of the wrapper to the front. This line MUST be parallel with the base. It needs to be done for the other side of the wrapper as well:

 

attachment.php?attachmentid=10955&d=1387806894

 

 

.... Looking very well altogether and very self explanatory. Well done sir.

 

Self-explanatory is the whole point. Feel free to use the photos to develop your instruction sheets, or possibly put them on an explanatory photo CD for buyers of the kit.

Edited by Horsetan
Weshty's comment added

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With the help of a 2mm axle, the reverse curves were formed. Everything below that transition curve must now be straightened. I'm repeating the photo posted earlier to show what the smokebox wrapper should look like:

 

attachment.php?attachmentid=11000&d=1388104066

 

I'm wondering whether I should solder it on to the shell now, which should allow me to line up the front frames, or wait until I've sorted the positioning of other parts.

 

Looking good, I look forward to the chassis build.

 

I'm not, mainly because I need to part-build the basic frames and leave room for the inside motion, motion brackets, etc. Although I've marked out for the CSB suspension, the front mounting point is missing because it's some way above the chassis top-line.....which means I have to solder in a bracket for it that was never there in real life :(

 

The bogie will also be assembled differently from the instructions, as I want it to help bear the wieght of the front end.

 

I'm wondering if I should start work on the tender in order to create more thinking time......?

Edited by Horsetan

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Self-explanatory is the whole point. Feel free to use the photos to develop your instruction sheets, or possibly put them on an explanatory photo CD for buyers of the kit.

 

Horsetan, thanks a mill for this, very much appreciated and I will take you up on the offer, anything that makes construction easier is very much welcome, and your construction thread certainly does this!

 

Happy new year.

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Horsetan, thanks a mill for this, very much appreciated and I will take you up on the offer, anything that makes construction easier is very much welcome, and your construction thread certainly does this!

 

Happy new year.

 

Happy New Year.

 

Anything that advances the cause of Irish finescale - and 4mm/21 in particular - has to be worth pursuing.

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Wonder of wonders, a quarter-size Dundalk drawing of the "S" class inside motion, dated November 1925, has just arrived in the post....:banana:

 

attachment.php?attachmentid=11512&d=1390658868

Edited by Horsetan

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And the weekend to peruse it. Sweet!

 

It's massive - takes up the entire dining table. I've updated the album so's ye can get an idea of the quarter-size scale.....!

 

attachment.php?attachmentid=11513&d=1390658868

 

Apparently, the design width between the frames is 4ft 8ins so my aim to have a spacer width of 17mm is well within what is allowable.

Edited by Horsetan

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They are fantastic Ivan. Even though a GAD can be useful the finished rolling stock isn't always the same. These are the real deal.

 

Rich,

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I was on a mission this morning picking up a live steam Basset Lowke 4-4-0

Spied something blue out of the corner of my good eye

A Harry Connaughton built Slieve Gullion in O Gauge!

Could not manage to take it off his hands but man, it was a stunner.

Could be up to 45 years old!

 

P1050745_zps01cf6d09.jpg

 

P1050744_zps877423d8.jpg

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Wow, that's beautiful, it isn't for sale, is it?

 

He wishes. :)

 

If there was even a hint that it was on offer I know Dave would've bitten his arm off!

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He wishes. :)

 

If there was even a hint that it was on offer I know Dave would've bitten his arm off!

 

It has taken on the status of Family Heirloom, he has grandchildren who are interested in model railways so my offer was graciously declined

I have taken out a subscription to RIP.IE just in case

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:drool:

 

^^

This.

 

An order will be made in the next week or so for a Finney T9 inside motion kit to try to make life a bit easier in respect of crossheads and slidebars......

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I was on a mission this morning picking up a live steam Basset Lowke 4-4-0

Spied something blue out of the corner of my good eye

A Harry Connaughton built Slieve Gullion in O Gauge!

Could not manage to take it off his hands but man, it was a stunner.

Could be up to 45 years old!

 

P1050745_zps01cf6d09.jpg

 

P1050744_zps877423d8.jpg

 

just seen these pics and she is a stunner - would kill for an oo gauge one!

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just seen these pics and she is a stunner - would kill for an oo gauge one!

 

Find yourself a builder and I'll see you right!

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Some more water has passed under the oul bridge. As I now do two jobs during the week, as well as helping to look after a Thoroughbred racehorse at weekends, modelling time has been severely cut down, but I haven't been totally idle.

 

Richard McLachlan of the IRRS has stumbled across some clearer motion drawings for the "S" - these are marked Dundalk drawing no.s 202N and 203N. He initially thought that they dated from the time when the "S" and "S2" were rebuilt in 1938, but the markings clearly show they were done at the end of 1925. With some of the known dimensions, I managed to reduce one down to 4mm scale, and the resultant copy is tiny but still just about legible!

 

attachment.php?attachmentid=15527&d=1413888088

 

attachment.php?attachmentid=15526&d=1413888075

 

The drawings also confirm that the distance between the frames is 4ft 8ins, so my original Maplin jig-spacer width of 16mm is almost there, though I am wondering if a few washers might help pad things out.

 

There are still a couple more drawings that I need - mostly of the cylinder block (103S and 105S), which is where things get interesting because the SSM kit smokebox frame partly extends downwards into the space where the piston valves of the inside cylinders should be!

 

I did manage to buy Martin Finney's inside motion kit for the LSWR T9, and was mighty pleased to find that the crossheads are almost exactly the right "+" cross-section for the "S", the matching slidebars and piston rod glands are adaptable, whilst the motion bracket looks like it could be split and widened to fit between the frames of the "S". I can use the cranks from the GW 1854/2721 inside motion kit as these are near-identical in shape to those on the "S".

 

This leaves the connecting rods themselves; it's 6ft 6ins (26mm in 4mm scale) between the centre of the "little end" and the centre of the "big end", so whether I adapt the rods from the GW or LSWR loco is not that important - the plain fact is that both types will need modifying!

 

At the moment the only scratchbuilt parts would appear to be the rockers and their brackets, as well as the back-end of the cylinder block.

 

A bit of work has been done on the cab - mainly the front overlay and the rear splasher tops:

 

attachment.php?attachmentid=15521&d=1413886904

 

attachment.php?attachmentid=15522&d=1413886917

 

It is important not to have any of it lopsided - all of the various holes and slots must line up with those on the inner cab structure, so it's out with the hairgrips again:

 

attachment.php?attachmentid=15523&d=1413886931

 

attachment.php?attachmentid=15524&d=1413886944

 

attachment.php?attachmentid=15525&d=1413886956

 

I found it was better to tack-solder the overlay in place before trying to form the splasher tops.

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It has been a journey - an essentially "simple"-looking 4-4-0 actually has quite a lot of parts crammed into it!

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Here's an overview of the original Finney inside motion parts - some of which will find their way into no.171:

 

attachment.php?attachmentid=15535&d=1413974190

 

The LSWR "T9" has 4-bar slidebars, matching cylinder glands and ends on the fret. The motion bracket also looks as if it could be adapted:

 

attachment.php?attachmentid=15536&d=1413974202

 

...but the real beauty is the pair of cast brass cruciform crossheads which lend themselves almost perfectly to 171's insides:

 

attachment.php?attachmentid=15537&d=1413974213

 

Here's the connecting and eccentric rods fret from the GW 2721:

 

attachment.php?attachmentid=15538&d=1413974227

 

....the connecting rods, at just short of 26mm centres, seem almost exactly right for 171, though a bit of lengthening wouldn't come amiss.

 

I was also sifting through the small pile of Brassmasters LMS loco kits that I have picked up secondhand over the years (never buy them new if ye want to save cash), and realised that the 4F also has working inside motion included in it, which almost immediately led me to consider if the motion bracket, rockers and reversing gear / counterweights could be adapted into the "S".

 

Glad to hear things are progressing with the S class.

 

I think I did hint that this wasn't going to be a quick build, but I'm so grateful to you for providing all those invaluable close-ups of 171's inside motion that most of us would never normally give a thought about.

Edited by Horsetan

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Good to see you have your modelling mojo up and running again. I shall enjoy watching such a meticulous build. hope its not too slow as I would like to see the finished loco! Mike

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.... I shall enjoy watching such a meticulous build. hope its not too slow as I would like to see the finished loco!

 

I read recently that the RPSI have abandoned any hope of bringing 171 back into steam this year (something to do with the implications of having all three surviving GNRI engines running all at once, and the consequences that will have on the budget when they all fall due for their next overhauls), and apparently it may be a few years before she returns to the rails of Ireland. Shame, really, as the whole prospect seemed to be going really well.

 

What would it cost to build a new full-size "VS", engine only?

 

171 being laid aside gives me a bit of a breather, and a sporting chance of going on with my own build.

 

The next stage I anticipate doing is the overlay for the cab front, plus the front frame sections above the footplate. The smokebox overlay and firebox will also need tidying up, now that I look at them.

 

In respect of the mainframes, I'd like to thank "Kirley" of this diocese for letting me have the leftover 21mm gauge spacers from his SG2 build. The nickel silver set are for the engine, whilst the brass ones are for the tender; initial checks show that these are exactly 16mm wide, matching the Maplin plastic hex spacers that I've been using to help the basic erection. Another spot of luck.

Edited by Horsetan
Update; weblink added

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I had a spare moment this afternoon, so finally managed to erect the upper frames into their proper place on the footplate. These consist of two etch layers each, sweated together (parts P16 and P17 on the body etch fret), and are the strengthened frames that 171 and her sisters were given when rebuilt in 1938:

 

attachment.php?attachmentid=25657&d=1477779168

 

The back edge of the frames stop at the exact point where the footplate opening for the driving wheel begins, and care is needed to ensure that they are perfectly vertical and spaced just enough to allow the smokebox to slide in between:

 

attachment.php?attachmentid=25658&d=1477779195

 

I think we can afford to plug the boiler and firebox into the cab front to have a look, so....

 

attachment.php?attachmentid=25659&d=1477779216

 

...the rear splasher tops can be formed. I curved them around a bottle screw cap of roughly the same radius as the splasher sides, and ended up with this:

 

attachment.php?attachmentid=25660&d=1477779231

 

She's looking a bit more together, but I don't think it would be the time to solder the splasher sides to the footplate, as I still want to be able to remove sub-assemblies to check clearances.

 

Just realised that the little etch for the reversing crank / lever stub has detached from the footplate, but this might not matter too much until I can get the inside motion scheme going.

 

When Terry MacDermott originally designed the kit, he came up with a fairly complex bogie pivoting system consisting of a rubbing plate which itself was pivoted from further back in the chassis. Although it clearly works, it isn't a system I can use because it potentially gets in the way of the connecting and eccentric rods, so I'm looking at a more self-contained idea such as that used by Brassmasters in its LMS loco kits, which allows the bogie to pivot and slide laterally, but which does not allow the bogie structure to rise and fall - instead, only the bogie wheels do that, just as on the real thing.

Edited by Horsetan
Updated thoughts

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That's looking well, Ivan:tumbsup:

 

Thanks. I've been reviewing the chassis frames this evening, and working out where I can squeeze in the mounting points for CSB suspension.

 

IMG_20161031_001312_1477872824854.jpg

 

The rear end of the cylinder block is what I'm dreading.

Edited by Horsetan
photo insert

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I was pleasantly relieved to find that the eccentric rods from the Finney GW 1854/2721 motion kit are virtually spot-on when it comes to the measurement between centres: the S-class 4'6" equates to 18mm in 4mm scale:

 

attachment.php?attachmentid=25713&d=1477956090

 

....so I can definitely use all four of these rods and the brass eccentric sheaves, as well as the cast inside cranks from the same motion kit which we already know to be the right shape.

 

I also discovered that the measurement between pivot and crankpin centres for the Finney LSWR T9 connecting rods corresponds exactly to the 6'6" distance of the S-class connecting rod:

 

attachment.php?attachmentid=25714&d=1477956811

 

Half the fun is finding out just what is possible with other people's etched parts; they've done all the hard work, so why not use them?

Edited by Horsetan
Adding photos

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These are the 21mm gauge spacers that Kirley kindly let me have:

 

attachment.php?attachmentid=25715&d=1477957816

 

They originate from the SSM "SG" loco kit, and being 16mm wide could be usefully adapted for the S-class chassis.

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